Vehicle doors are typically constructed with two or more panels attached to the door frame, including an exterior panel for shielding the passenger compartment from the elements, an inner door panel which provides structural support, and a trim panel facing the passenger compartment. The trim panel is usually fastened to the inner door panel and shields the vehicle occupants from internal door components, such as the window, the window regulator, and the door locks. The trim panel can also provide aesthetic qualities to the interior passenger compartment as well as ergonomic features, for example, easily accessible door handles, mirror and window controls, and the like.
Fastening of the trim panel to the inner door panel is conventionally accomplished by a plurality of trim panel mounted retaining pins which fit through associated openings in the inner door panel. Each retaining pin is secured to a pin receiving bracket, or boss, on the face of the trim panel adjacent the inner door panel. In addition to providing a means for attachment, the retaining pins also can incorporate moisture control devices and energy absorption characteristics.
The energy absorption characteristics of a trim panel play an important role in automotive design from an occupant kinematics standpoint. Several approaches have been taken to integrate energy absorption principles into trim panel designs. For example, foam can be attached to the trim panel to absorb energy from excessive side loading of the vehicle during the impact loading attendant a collision, as is disclosed in U.S. Pat. No. 4,890,877 (Ashtiani-Zarandi et al.). Energy absorption can also be accomplished by mounting spring suspended steel straps between the trim panel and inner door panel, as shown in U.S. Pat. No. 5,048,234 (Lau et al.).
Other devices for energy absorption in a vehicle door provide a shock absorbing feature in the fasteners between the inner door panel and the trim panel. One such device, shown in U.S. Pat. No. 5,169,204 (Kelman), discloses a plurality of fasteners having damping means along the shaft to absorb axial forces. In Japanese Patent 231,246 (Ishikawa), impact force is absorbed by shifting a pin through a core member. These devices rely on compression of a portion of the retaining pin to effect energy absorption, unlike the present invention which relies on collapsing of the retaining pin boss along predetermined sections of varying thickness for energy absorption.